Why is the introduction of genetically engineered lymphocytes into a ADA deficiency patient not a permanent cure ? Suggest a possible permanent cure.

Explanation

### Step-by-Step Solution:

1. **Understanding ADA Deficiency**:
- ADA (Adenosine Deaminase) deficiency is a genetic disorder that affects the immune system. Individuals with this condition lack the enzyme ADA, which is crucial for the breakdown of toxic metabolites in lymphocytes. This leads to a compromised immune system.

2. **Introduction of Genetically Engineered Lymphocytes**:
- In current treatments, lymphocytes (a type of white blood cell) from the patient are genetically engineered to express the ADA enzyme. These modified lymphocytes are then infused back into the patient.

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